A tube that is shoved up someone's ass. Liquids are then able to be passed through the tube into the person's anal cavity therefore giving them special sensations.
I shoved that asstube into Alby's ass and then I filled his ass with piss and rocketsauce.
by speedman225 March 16, 2007
Word used to describe an asshole when specifically suggesting that the person is the tube-like, shit-covered skin within the anus, rather than the air between it.
That guy just stole my seat! What an ass tube!
by Carton Jones December 16, 2008